1. Field of the Invention
This invention relates to a slider for slide fastener and has particular reference to a slider having an automatic lock function.
2. Prior Art
There are known numerous automatic lock sliders for slide fasteners.
FIGS. 6 and 7 of the accompanying drawings illustrate a prior art slider encountered with a problem which the present invention seeks to overcome. The prior art slider disclosed in German Patent No. 842632 comprises a slider body 100, a lug or trunnion 110 integrally formed on the top surface of the body 100, a locking spring member 120 interposed between the body 100 and the lug 110 and having a locking prong 130 normally urged downwardly into a guide channel 140 in the body 100 for the passage therethrough of a pair of opposed coupling element rows of a slide fastener (not shown). The locking spring member 120 adapted to lock the slide fastener against longitudinal movement has a profile shown in FIG. 7 and includes a cut-out tongue 150 resting against the bottom wall of the lug 110. The slider body 100 has a mound 160 at its rear end over which the spring member 120 is bent. A pull tab 170 for moving the slider has its pivotal end 180 disposed underneath the spring member 120. When moving this prior art slider in a direction to close the slide fastener; i.e. toward the left as viewed on FIG. 6, this is done by rotating the pull tab 170 counter-clockwise into a position beyond a vertical axis of the slider body 100. However, due to the structural features of the slider illustrated in FIG. 6, the spring member 120 is prone to move back down at its rear end against upward pull exerted by the pull tab 170 so that the locking prong 130 fails to retract away from the passage of the fastener element rows and tends to scratch the surfaces of the latter during closing operation of the slider.